Nitrogen losses from integrated rice-duck and rice-fish ecosystems in southern China

作者:Li Cheng fang; Cao Cou gui*; Wang Jin ping; Ming Zhan; Yuan Wei ling; Ahmad Shahrear
来源:Plant and Soil, 2008, 307(1-2): 207-217.
DOI:10.1007/s11104-008-9597-1

摘要

Nitrogen (N) losses via nitrous oxide (N2O) emission, ammonia (NH3) volatilization and N leaching were investigated from N fertilizer applied to integrated rice-duck and rice-fish ecosystems in southern China. N2O emissions was measured by a static chambers technique, NH3 volatilization by a closed acid trap method, and N leaching by a field lysimeter. The experimental field was equally divided into nine plots for three different treatments: (1) conventional rice field (CK), (2) rice-duck ecosystem (RD) and (3) rice-fish ecosystem (RF). N2O emissions from fertilizer was affected by fertilization and drainage of paddy fields. RD significantly increased N2O emissions while RF decreased N2O emissions. N losses via N2O emissions in CK, RD and RF were 1.94, 2.19 and 1.91 kg N/ha, respectively. N losses via NH3 volatilization in CK, RD and RF were 46.30, 43.09 and 44.89 kg N/ha, respectively. Due to the presence of ducks and fish, RD and RF decreased N losses via NH3 volatilization and leakage of NO3- and total N. N losses via NO3- leaching in CK, RD and RF were 2.83, 2.57 and 2.45 kg N/ha, respectively, and N losses via total N leaching were 6.73, 6.11 and 5.81 kg N/ha, respectively. Analysis of total N losses via N2O emission, NH3 volatilization and N leaching indicated that total N losses in RD and RF were 51.39 and 52.60 kg N/ha, respectively, which were lower than that (54.97 kg N/ha) in CK, suggesting that the presence of ducks and fish could decrease N fertilizer loss rates, and thus promote N fertilizer use efficiency.